1. Field of the Invention
The present invention relates to a water jet propeller having an impeller disposed inside an impeller housing and making the impeller rotate to expel a water jet.
2. Description of Background Art
Conventionally, the water jet propeller is mounted in a rear portion of a hull and draws in water from a hull bottom by driving the impeller with an engine and expelling the water drawn therein rearward, thereby propelling a watercraft See, for example, Japanese Patent Laid-open No. Hei 9-99897.
The art disclosed in Japanese Patent Laid-open No. Hei 9-99897 will be described with reference to FIG. 11.
FIG. 11 is a view for illustrating a basic construction of the conventional water jet propeller.
A water jet propeller 200 includes an impeller housing 203, a stator 204, a nozzle 205, and a steering nozzle 207. The impeller housing 203, of a cylindrical shape, is disposed in a rear portion 202 of a hull 201. The stator 204, of a cylindrical shape, is disposed at a rear-end portion 203a of the impeller housing 203. The nozzle 205 having a diminishing diameter rearwardly is disposed at a rear-end portion 204a of the stator 204. The steering nozzle 207 is fitted to the nozzle 205 via upper and lower pins 206, 206 swingably in a crosswise direction.
An impeller 208 is disposed inside the impeller housing 203. A rotational shaft 209 of the impeller 208 is extended to reach into the stator 204. The extended rotational shaft 209 is rotatably mounted in the stator 204 via bearings 211, 211.
According to the water jet propeller 200, the impeller 208 disposed inside the impeller housing 203 is rotated by an engine (not shown). A water jet is thereby expelled from a rear-end portion 207a of the steering nozzle 207 to propel the hull 201.
The steering nozzle 207 is swung to the right or to the left about an axis of the upper and lower pins 206, 206, thereby allowing the hull 201 to turn right or left.
The water jet propeller 200 generally uses a connection bolt (not shown) as means for mounting the impeller housing 203, the stator 204, and the nozzle 205 integrally together.
More specifically, each of the impeller housing 203, the stator 204, and the nozzle 205 includes a mounting portion (not shown) disposed on an outer wall thereof. The connection bolt is passed through the mounting portion of the impeller housing 203, the mounting portion of the stator 204, and the mounting portion of the nozzle 205. The impeller housing 203, the stator 204, and the nozzle 205 are thereby connected integrally together.
The water jet propeller 200 may be disassembled for purposes of, for example, performing a service job, by removing the connection bolt. In such cases, the impeller housing 203, the stator 204, and the nozzle 205 can be separated from each other.
It is to be noted herein that the rotational shaft 209 of the impeller 208 is extended to reach into the stator 204. The extended rotational shaft 209 is rotatably mounted in the stator 204 via the bearings 211, 211.
Accordingly, when the impeller housing 203, the stator 204, and the nozzle 205 are separated from each other, the impeller 208 and the stator 204 are integrally separated from the impeller housing 203 or the nozzle 205.
As a result, the impeller 208 is removed from the impeller housing 203 and exposed.
It is therefore an object of the present invention to provide a water jet propeller that prevents the impeller from being exposed when the water jet propeller is disassembled.